1. Field of the Invention
The present invention relates to a communication systems, and more particularly to a system and method for identifying one or more signaling channels during communication between a controller and a remote system component.
2. Description of the Related Art
High speed communication lines form the backbone of any telecommunication system. Typically, these lines connect various components of the telecommunication system and end users, thereby forming a system network and enabling high speed voice and data transfers between system components and end users. Additionally, high speed wireless communication links perform similar functions and are utilized in a similar manner.
The operation of the telecommunication system is commonly controlled from one or more controllers distributed throughout the system network. Control signals from the controllers are transmitted to various system components via the high speed communication lines or links along with signals carrying voice and data. These signals commonly contain control and maintenance information. Control information is used to establish and maintain communication connections between system components and the controller and also between system components and end users who receive and transmit video, voice and/or data through the connections. Maintenance information is used to initialize system components, to recover system components from errors and to monitor and manage their performance. The transmission of control and maintenance information between the controller and system components is commonly referred to as intra-system xe2x80x9csignalingxe2x80x9d, or simply signaling.
Many high speed communication lines use a channelized format where the total bandwidth of a line is split into a predefined number of separate transmission channels or xe2x80x9cslotsxe2x80x9d. For example, a T1 line has 24 separate 64 Kilobits per second (Kbps) channels (hereinafter referred to as xe2x80x9cDS0 time slotsxe2x80x9d), while an E1 line has 32 such slots. Most of the slots are used to carry end-user information such as data and voice transmissions that are carried by the telecommunications system as part of the primary communications service offered by the system. In each communication line, one or more of the DS0 time slots are used to carry the control signals. Similarly, wireless communication links also utilize channelized transmission formats.
In many previously known systems, the particular channels used for signaling are rigidly defined, i.e. xe2x80x9chard-coded,xe2x80x9d in the system hardware or firmware, or predefined in the system software, or configured by manual intervention during the setup of the equipment. Thus, in such arrangements system components always receive control signals via particular predefined channels. This arrangement is problematic, because in many instances service providers, who use system components to provide communication services to end users, each lease only a fraction of a communication line. Thus, service providers may not have access to the particular signaling channel that is not in their leased fraction of the line and, as a result, their system component has no access to remote signaling from the system controller. The problem is further exacerbated by the fact that the service provider must configure each component to the specific configuration suitable to the particular facilities provided on the available link.
It would thus be desirable to enable any channel of a multi-channel communication line or a wireless link to be used for transmission of control signals. It would further be desirable to enable a system component to automatically locate one or more signaling channels carrying control signals from a remote system controller to permit reception of control signals and to initiate communication therebetween.
The system and method of the invention enable any channel of a multi-channel communication link to be used for transmission of a control signal (hereinafter xe2x80x9csignalingxe2x80x9d) by a system controller. A system component automatically locates one or more signaling channels and then establishes communication with the controller when the one or more of the channels have been located. If no signaling channels are located after a predetermined number of attempts or after a predetermined period of time, the system component may attempt to reinitialize the interface or diagnose the problem within it; these procedures are escalated and culminate in a full reset of the component, if required, before continuing to search for the signaling channels.
In accordance with the invention, a communications system is provided with a system controller for controlling the system""s operation and for transmitting a control signal to a system component, a system component for providing communication services to end users, and a communication link capable of sending and receiving information units on multiple distinct physical or logical channels connecting the system controllers and the system component and having one or more channels available for carrying one or more control signals transmitted by the system controller to the system component. The system component includes a component controller for controlling the operation of the system component, for identifying and receiving the control signal from the system controller and for initiating communication with the system controller when the control signal is received. The system component may also include a component memory for a stored control program used to implement the procedures and protocols executed by the component controller when communication between the system component and the system controller is established; the system may elect to implement the procedures and protocols in hardware using a dedicated Application Specific Integrated Circuit (ASIC).
The control signal includes initialization information for the system component as well as instructions for establishing a communication connection between the system component and the system controller using an appropriate predetermined communication protocol. The control signal also includes a unique identifier for identifying, to the system component, the channel that is carrying the control signal as a signaling channel. The control signal is intermittently transmitted by the system controller to the system component on one or more of the communication link""s channels. The combination of any or all of protocol, control signal format, control signal encoding, and unique identifier may be used by the system component to perform the selection of the proper channel; upon selection, further procedures in the protocol can be implemented to confirm the proper selection and/or to authenticate the system component for further transaction with the system controller.
In one embodiment of the present invention, the system controller periodically transmits the control signal to the system component in a selected channel of the multi-channel communication link. In another embodiment of the invention, the system controller may transmit the control signal only when communication connections to one or more system components have failed or have not yet been established. Optionally, another system controller also transmits one or more additional control signals in one or more additional signaling channels. The original control signal as well as the additional control signals optionally each include an identification code that identifies all other signaling channels, so that when the component controller locates one signaling channel, it may readily identify all other signaling channels.
The component controller first initializes the system component and begins to search, for a time period xe2x80x9cNxe2x80x9d, all channels of the communication link to identify the particular signaling channel. If the signaling channel is not found during the time period N, then the component controller determines whether the system component performs appropriate internal recovery actions and escalates these until the only remaining option is that the system should be reset, and resets the system component as necessary before re-starting the search. If the signaling channel is found during the time period N, then the component controller establishes a communication connection with the system controller in accordance with the control signal carried by the signaling channel.
Once a successful communication connection has been established, the operation and performance of the system component may be remotely controlled and monitored by the system controller through the connection. In addition, the communication application stored in the component memory is then initialized. If the communication application successfully initializes within a time period xe2x80x9cTxe2x80x9d, then the component controller executes the communication application. If the communication application does not initialize within the time period T, it is likely that the application may require additional control signals for proper initialization. Accordingly, the component controller continues to search the communication link to identify the additional channels and to receive the additional control signals communicated thereon so that the communication application may properly initialize.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims.